The term DECLINE TO PARTICIPATE can be broken down into three crossword solutions: PASS (4 letters), SAYNO (5 letters), and OPTOUT (6 letters). PASS is an abbreviation of the phrase 'PASS on, ' which means to decline or refuse an offer or invitation. SAYNO is a combination of the words 'SAY' and 'NO, ' which are used to express refusal or dissent. OPTOUT is a verb meaning to choose not to participate in something. All three terms refer to the act of declining to take part in something.